/**
 * Encodes and decodes to and from Base64 notation.
 * 
 * <p>
 * Change Log:
 * </p>
 * <ul>
 * <li>v2.1 - Cleaned up javadoc comments and unused variables and methods.
 * Added some convenience methods for reading and writing to and from files.</li>
 * <li>v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on
 * systems with other encodings (like EBCDIC).</li>
 * <li>v2.0.1 - Fixed an error when decoding a single byte, that is, when the
 * encoded data was a single byte.</li>
 * <li>v2.0 - I got rid of methods that used booleans to set options. Now
 * everything is more consolidated and cleaner. The code now detects when data
 * that's being decoded is gzip-compressed and will decompress it automatically.
 * Generally things are cleaner. You'll probably have to change some method
 * calls that you were making to support the new options format (<tt>int</tt>s
 * that you "OR" together).</li>
 * <li>v1.5.1 - Fixed bug when decompressing and decoding to a byte[] using
 * <tt>decode( String s, boolean gzipCompressed )</tt>. Added the ability to
 * "suspend" encoding in the Output Stream so you can turn on and off the
 * encoding if you need to embed base64 data in an otherwise "normal" stream
 * (like an XML file).</li>
 * <li>v1.5 - Output stream pases on flush() command but doesn't do anything
 * itself. This helps when using GZIP streams. Added the ability to
 * GZip-compress objects before encoding them.</li>
 * <li>v1.4 - Added helper methods to read/write files.</li>
 * <li>v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.</li>
 * <li>v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input
 * stream where last buffer being read, if not completely full, was not
 * returned.</li>
 * <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the
 * wrong time.</li>
 * <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li>
 * </ul>
 * 
 * <p>
 * I am placing this code in the Public Domain. Do with it as you will. This
 * software comes with no guarantees or warranties but with plenty of
 * well-wishing instead! Please visit <a
 * href="http://iharder.net/base64">http://iharder.net/base64</a> periodically
 * to check for updates or to contribute improvements.
 * </p>
 * 
 * @author Robert Harder
 * @author rob@iharder.net
 * @version 2.0
 */
package com.toolsverse.util.encryption;

public class Base64
{
    
    /* ******** P U B L I C F I E L D S ******** */

    /**
     * A {@link Base64.InputStream} will read data from another
     * <tt>java.io.InputStream</tt>, given in the constructor, and encode/decode
     * to/from Base64 notation on the fly.
     * 
     * @see Base64
     * @since 1.3
     */
    public static class InputStream extends java.io.FilterInputStream
    {
        private boolean encode; // Encoding or decoding
        private int position; // Current position in the buffer
        private byte[] buffer; // Small buffer holding converted data
        private int bufferLength; // Length of buffer (3 or 4)
        private int numSigBytes; // Number of meaningful bytes in the buffer
        private int lineLength;
        private boolean breakLines; // Break lines at less than 80 characters
        
        /**
         * Constructs a {@link Base64.InputStream} in DECODE mode.
         * 
         * @param in
         *            the <tt>java.io.InputStream</tt> from which to read data.
         * @since 1.3
         */
        public InputStream(java.io.InputStream in)
        {
            this(in, DECODE);
        } // end constructor
        
        /**
         * Constructs a {@link Base64.InputStream} in either ENCODE or DECODE
         * mode.
         * <p>
         * Valid options:
         * 
         * <pre>
         *   ENCODE or DECODE: Encode or Decode as data is read.
         *   DONT_BREAK_LINES: don't break lines at 76 characters
         *     (only meaningful when encoding)
         *     &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
         * </pre>
         * <p>
         * Example: <code>new Base64.InputStream( in, Base64.DECODE )</code>
         * 
         * 
         * @param in
         *            the <tt>java.io.InputStream</tt> from which to read data.
         * @param options
         *            Specified options
         * @see Base64#ENCODE
         * @see Base64#DECODE
         * @see Base64#DONT_BREAK_LINES
         * @since 1.0
         */
        public InputStream(java.io.InputStream in, int options)
        {
            super(in);
            this.breakLines = (options & DONT_BREAK_LINES) != DONT_BREAK_LINES;
            this.encode = (options & ENCODE) == ENCODE;
            this.bufferLength = encode ? 4 : 3;
            this.buffer = new byte[bufferLength];
            this.position = -1;
            this.lineLength = 0;
        } // end constructor
        
        /**
         * Reads enough of the input stream to convert to/from Base64 and
         * returns the next byte.
         * 
         * @return next byte
         * @since 1.3
         */
        @Override
        public int read()
            throws java.io.IOException
        {
            // Do we need to get data?
            if (position < 0)
            {
                if (encode)
                {
                    byte[] b3 = new byte[3];
                    int numBinaryBytes = 0;
                    for (int i = 0; i < 3; i++)
                    {
                        try
                        {
                            int b = in.read();
                            
                            // If end of stream, b is -1.
                            if (b >= 0)
                            {
                                b3[i] = (byte)b;
                                numBinaryBytes++;
                            } // end if: not end of stream
                            
                        } // end try: read
                        catch (java.io.IOException e)
                        {
                            // Only a problem if we got no data at all.
                            if (i == 0)
                                throw e;
                            
                        } // end catch
                    } // end for: each needed input byte
                    
                    if (numBinaryBytes > 0)
                    {
                        encode3to4(b3, 0, numBinaryBytes, buffer, 0);
                        position = 0;
                        numSigBytes = 4;
                    } // end if: got data
                    else
                    {
                        return -1;
                    } // end else
                } // end if: encoding
                
                // Else decoding
                else
                {
                    byte[] b4 = new byte[4];
                    int i = 0;
                    for (i = 0; i < 4; i++)
                    {
                        // Read four "meaningful" bytes:
                        int b = 0;
                        do
                        {
                            b = in.read();
                        }
                        while (b >= 0 && DECODABET[b & 0x7f] <= WHITE_SPACE_ENC);
                        
                        if (b < 0)
                            break; // Reads a -1 if end of stream
                            
                        b4[i] = (byte)b;
                    } // end for: each needed input byte
                    
                    if (i == 4)
                    {
                        numSigBytes = decode4to3(b4, 0, buffer, 0);
                        position = 0;
                    } // end if: got four characters
                    else if (i == 0)
                    {
                        return -1;
                    } // end else if: also padded correctly
                    else
                    {
                        // Must have broken out from above.
                        throw new java.io.IOException(
                                "Improperly padded Base64 input.");
                    } // end
                    
                } // end else: decode
            } // end else: get data
            
            // Got data?
            if (position >= 0)
            {
                // End of relevant data?
                if ( /* !encode && */position >= numSigBytes)
                    return -1;
                
                if (encode && breakLines && lineLength >= MAX_LINE_LENGTH)
                {
                    lineLength = 0;
                    return '\n';
                } // end if
                else
                {
                    lineLength++; // This isn't important when decoding
                    // but throwing an extra "if" seems
                    // just as wasteful.
                    
                    int b = buffer[position++];
                    
                    if (position >= bufferLength)
                        position = -1;
                    
                    return b & 0xFF; // This is how you "cast" a byte that's
                    // intended to be unsigned.
                } // end else
            } // end if: position >= 0
            
            // Else error
            else
            {
                // When JDK1.4 is more accepted, use an assertion here.
                throw new java.io.IOException(
                        "Error in Base64 code reading stream.");
            } // end else
        } // end read
        
        /**
         * Calls {@link #read()} repeatedly until the end of stream is reached
         * or <var>len</var> bytes are read. Returns number of bytes read into
         * array or -1 if end of stream is encountered.
         * 
         * @param dest
         *            array to hold values
         * @param off
         *            offset for array
         * @param len
         *            max number of bytes to read into array
         * @return bytes read into array or -1 if end of stream is encountered.
         * @since 1.3
         */
        @Override
        public int read(byte[] dest, int off, int len)
            throws java.io.IOException
        {
            int i;
            int b;
            for (i = 0; i < len; i++)
            {
                b = read();
                
                // if( b < 0 && i == 0 )
                // return -1;
                
                if (b >= 0)
                    dest[off + i] = (byte)b;
                else if (i == 0)
                    return -1;
                else
                    break; // Out of 'for' loop
            } // end for: each byte read
            return i;
        } // end read
        
    } // end inner class InputStream
    
    /**
     * A {@link Base64.OutputStream} will write data to another
     * <tt>java.io.OutputStream</tt>, given in the constructor, and
     * encode/decode to/from Base64 notation on the fly.
     * 
     * @see Base64
     * @since 1.3
     */
    public static class OutputStream extends java.io.FilterOutputStream
    {
        private boolean encode;
        private int position;
        private byte[] buffer;
        private int bufferLength;
        private int lineLength;
        private boolean breakLines;
        private byte[] b4; // Scratch used in a few places
        private boolean suspendEncoding;
        
        /**
         * Constructs a {@link Base64.OutputStream} in ENCODE mode.
         * 
         * @param out
         *            the <tt>java.io.OutputStream</tt> to which data will be
         *            written.
         * @since 1.3
         */
        public OutputStream(java.io.OutputStream out)
        {
            this(out, ENCODE);
        } // end constructor
        
        /**
         * Constructs a {@link Base64.OutputStream} in either ENCODE or DECODE
         * mode.
         * <p>
         * Valid options:
         * 
         * <pre>
         *   ENCODE or DECODE: Encode or Decode as data is read.
         *   DONT_BREAK_LINES: don't break lines at 76 characters
         *     (only meaningful when encoding)
         *     &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
         * </pre>
         * <p>
         * Example: <code>new Base64.OutputStream( out, Base64.ENCODE )</code>
         * 
         * @param out
         *            the <tt>java.io.OutputStream</tt> to which data will be
         *            written.
         * @param options
         *            Specified options.
         * @see Base64#ENCODE
         * @see Base64#DECODE
         * @see Base64#DONT_BREAK_LINES
         * @since 1.3
         */
        public OutputStream(java.io.OutputStream out, int options)
        {
            super(out);
            this.breakLines = (options & DONT_BREAK_LINES) != DONT_BREAK_LINES;
            this.encode = (options & ENCODE) == ENCODE;
            this.bufferLength = encode ? 3 : 4;
            this.buffer = new byte[bufferLength];
            this.position = 0;
            this.lineLength = 0;
            this.suspendEncoding = false;
            this.b4 = new byte[4];
        } // end constructor
        
        /**
         * Flushes and closes (I think, in the superclass) the stream.
         * 
         * @since 1.3
         */
        @Override
        public void close()
            throws java.io.IOException
        {
            // 1. Ensure that pending characters are written
            flushBase64();
            
            // 2. Actually close the stream
            // Base class both flushes and closes.
            super.close();
            
            buffer = null;
            out = null;
        } // end close
        
        /**
         * Method added by PHIL. [Thanks, PHIL. -Rob] This pads the buffer
         * without closing the stream.
         */
        public void flushBase64()
            throws java.io.IOException
        {
            if (position > 0)
            {
                if (encode)
                {
                    out.write(encode3to4(b4, buffer, position));
                    position = 0;
                } // end if: encoding
                else
                {
                    throw new java.io.IOException(
                            "Base64 input not properly padded.");
                } // end else: decoding
            } // end if: buffer partially full
            
        } // end flush
        
        /**
         * Resumes encoding of the stream. May be helpful if you need to embed a
         * piece of base640-encoded data in a stream.
         * 
         * @since 1.5.1
         */
        public void resumeEncoding()
        {
            this.suspendEncoding = false;
        } // end resumeEncoding
        
        /**
         * Suspends encoding of the stream. May be helpful if you need to embed
         * a piece of base640-encoded data in a stream.
         * 
         * @since 1.5.1
         */
        public void suspendEncoding()
            throws java.io.IOException
        {
            flushBase64();
            this.suspendEncoding = true;
        } // end suspendEncoding
        
        /**
         * Calls {@link #write(int)} repeatedly until <var>len</var> bytes are
         * written.
         * 
         * @param theBytes
         *            array from which to read bytes
         * @param off
         *            offset for array
         * @param len
         *            max number of bytes to read into array
         * @since 1.3
         */
        @Override
        public void write(byte[] theBytes, int off, int len)
            throws java.io.IOException
        {
            // Encoding suspended?
            if (suspendEncoding)
            {
                super.out.write(theBytes, off, len);
                return;
            } // end if: supsended
            
            for (int i = 0; i < len; i++)
            {
                write(theBytes[off + i]);
            } // end for: each byte written
            
        } // end write
        
        /**
         * Writes the byte to the output stream after converting to/from Base64
         * notation. When encoding, bytes are buffered three at a time before
         * the output stream actually gets a write() call. When decoding, bytes
         * are buffered four at a time.
         * 
         * @param theByte
         *            the byte to write
         * @since 1.3
         */
        @Override
        public void write(int theByte)
            throws java.io.IOException
        {
            // Encoding suspended?
            if (suspendEncoding)
            {
                super.out.write(theByte);
                return;
            } // end if: supsended
            
            // Encode?
            if (encode)
            {
                buffer[position++] = (byte)theByte;
                if (position >= bufferLength) // Enough to encode.
                {
                    out.write(encode3to4(b4, buffer, bufferLength));
                    
                    lineLength += 4;
                    if (breakLines && lineLength >= MAX_LINE_LENGTH)
                    {
                        out.write(NEW_LINE);
                        lineLength = 0;
                    } // end if: end of line
                    
                    position = 0;
                } // end if: enough to output
            } // end if: encoding
            
            // Else, Decoding
            else
            {
                // Meaningful Base64 character?
                if (DECODABET[theByte & 0x7f] > WHITE_SPACE_ENC)
                {
                    buffer[position++] = (byte)theByte;
                    if (position >= bufferLength) // Enough to output.
                    {
                        int len = Base64.decode4to3(buffer, 0, b4, 0);
                        out.write(b4, 0, len);
                        // out.write( Base64.decode4to3( buffer ) );
                        position = 0;
                    } // end if: enough to output
                } // end if: meaningful base64 character
                else if (DECODABET[theByte & 0x7f] != WHITE_SPACE_ENC)
                {
                    throw new java.io.IOException(
                            "Invalid character in Base64 data.");
                } // end else: not white space either
            } // end else: decoding
        } // end write
        
    } // end inner class OutputStream
    
    /** No options specified. Value is zero. */
    public final static int NO_OPTIONS = 0;
    
    /** Specify encoding. */
    public final static int ENCODE = 1;
    
    /** Specify decoding. */
    public final static int DECODE = 0;
    
    /* ******** P R I V A T E F I E L D S ******** */

    /** Specify that data should be gzip-compressed. */
    public final static int GZIP = 2;
    
    /** Don't break lines when encoding (violates strict Base64 specification) */
    public final static int DONT_BREAK_LINES = 8;
    
    /** Maximum line length (76) of Base64 output. */
    private final static int MAX_LINE_LENGTH = 76;
    
    /** The equals sign (=) as a byte. */
    private final static byte EQUALS_SIGN = (byte)'=';
    
    /** The new line character (\n) as a byte. */
    private final static byte NEW_LINE = (byte)'\n';
    /** Preferred encoding. */
    private final static String PREFERRED_ENCODING = "UTF-8";
    
    /** The 64 valid Base64 values. */
    private final static byte[] ALPHABET;
    
    private final static byte[] _NATIVE_ALPHABET = /*
                                                    * May be something funny
                                                    * like EBCDIC
                                                    */
    {(byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F',
            (byte)'G', (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L',
            (byte)'M', (byte)'N', (byte)'O', (byte)'P', (byte)'Q', (byte)'R',
            (byte)'S', (byte)'T', (byte)'U', (byte)'V', (byte)'W', (byte)'X',
            (byte)'Y', (byte)'Z', (byte)'a', (byte)'b', (byte)'c', (byte)'d',
            (byte)'e', (byte)'f', (byte)'g', (byte)'h', (byte)'i', (byte)'j',
            (byte)'k', (byte)'l', (byte)'m', (byte)'n', (byte)'o', (byte)'p',
            (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', (byte)'v',
            (byte)'w', (byte)'x', (byte)'y', (byte)'z', (byte)'0', (byte)'1',
            (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7',
            (byte)'8', (byte)'9', (byte)'+', (byte)'/'};
    
    /**
     * Translates a Base64 value to either its 6-bit reconstruction value or a
     * negative number indicating some other meaning.
     **/
    private final static byte[] DECODABET = {-9, -9, -9, -9, -9, -9, -9, -9,
            -9, // Decimal 0 - 8
            -5, -5, // Whitespace: Tab and Linefeed
            -9, -9, // Decimal 11 - 12
            -5, // Whitespace: Carriage Return
            -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 -
                                                                // 26
            -9, -9, -9, -9, -9, // Decimal 27 - 31
            -5, // Whitespace: Space
            -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
            62, // Plus sign at decimal 43
            -9, -9, -9, // Decimal 44 - 46
            63, // Slash at decimal 47
            52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
            -9, -9, -9, // Decimal 58 - 60
            -1, // Equals sign at decimal 61
            -9, -9, -9, // Decimal 62 - 64
            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through
                                                          // 'N'
            14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O'
                                                            // through 'Z'
            -9, -9, -9, -9, -9, -9, // Decimal 91 - 96
            26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a'
                                                                // through 'm'
            39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n'
                                                                // through 'z'
            -9, -9, -9, -9 // Decimal 123 - 126
    /*
     * ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 127 - 139
     * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 140 - 152
     * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 153 - 165
     * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 166 - 178
     * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 179 - 191
     * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 192 - 204
     * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 205 - 217
     * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 218 - 230
     * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 231 - 243
     * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9 // Decimal 244 - 255
     */
    };
    // I think I end up not using the BAD_ENCODING indicator.
    // private final static byte BAD_ENCODING = -9; // Indicates error in
    // encoding
    private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in
                                                    // encoding
    
    private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in
                                                    // encoding
    
    /* ******** E N C O D I N G M E T H O D S ******** */

    /** Determine which ALPHABET to use. */
    static
    {
        byte[] __bytes;
        try
        {
            __bytes = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
                    .getBytes(PREFERRED_ENCODING);
        } // end try
        catch (java.io.UnsupportedEncodingException use)
        {
            __bytes = _NATIVE_ALPHABET; // Fall back to native encoding
        } // end catch
        ALPHABET = __bytes;
    } // end static
    
    /**
     * Very low-level access to decoding ASCII characters in the form of a byte
     * array. Does not support automatically gunzipping or any other "fancy"
     * features.
     * 
     * @param source
     *            The Base64 encoded data
     * @param off
     *            The offset of where to begin decoding
     * @param len
     *            The length of characters to decode
     * @return decoded data
     * @since 1.3
     */
    public static byte[] decode(byte[] source, int off, int len)
    {
        int len34 = len * 3 / 4;
        byte[] outBuff = new byte[len34]; // Upper limit on size of output
        int outBuffPosn = 0;
        
        byte[] b4 = new byte[4];
        int b4Posn = 0;
        int i = 0;
        byte sbiCrop = 0;
        byte sbiDecode = 0;
        for (i = off; i < off + len; i++)
        {
            sbiCrop = (byte)(source[i] & 0x7f); // Only the low seven bits
            sbiDecode = DECODABET[sbiCrop];
            
            if (sbiDecode >= WHITE_SPACE_ENC) // White space, Equals sign or
                                              // better
            {
                if (sbiDecode >= EQUALS_SIGN_ENC)
                {
                    b4[b4Posn++] = sbiCrop;
                    if (b4Posn > 3)
                    {
                        outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn);
                        b4Posn = 0;
                        
                        // If that was the equals sign, break out of 'for' loop
                        if (sbiCrop == EQUALS_SIGN)
                            break;
                    } // end if: quartet built
                    
                } // end if: equals sign or better
                
            } // end if: white space, equals sign or better
            else
            {
                System.err.println("Bad Base64 input character at " + i + ": "
                        + source[i] + "(decimal)");
                return null;
            } // end else:
        } // each input character
        
        byte[] out = new byte[outBuffPosn];
        System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
        return out;
    } // end decode
    
    /**
     * Decodes data from Base64 notation, automatically detecting
     * gzip-compressed data and decompressing it.
     * 
     * @param s
     *            the string to decode
     * @return the decoded data
     * @since 1.4
     */
    public static byte[] decode(String s)
    {
        byte[] bytes;
        try
        {
            bytes = s.getBytes(PREFERRED_ENCODING);
        } // end try
        catch (java.io.UnsupportedEncodingException uee)
        {
            bytes = s.getBytes();
        } // end catch
        // </change>
        
        // Decode
        bytes = decode(bytes, 0, bytes.length);
        
        // Check to see if it's gzip-compressed
        // GZIP Magic Two-Byte Number: 0x8b1f (35615)
        if (bytes != null && bytes.length >= 4)
        {
            
            int head = (bytes[0] & 0xff) | ((bytes[1] << 8) & 0xff00);
            if (java.util.zip.GZIPInputStream.GZIP_MAGIC == head)
            {
                java.io.ByteArrayInputStream bais = null;
                java.util.zip.GZIPInputStream gzis = null;
                java.io.ByteArrayOutputStream baos = null;
                byte[] buffer = new byte[2048];
                int length = 0;
                
                try
                {
                    baos = new java.io.ByteArrayOutputStream();
                    bais = new java.io.ByteArrayInputStream(bytes);
                    gzis = new java.util.zip.GZIPInputStream(bais);
                    
                    while ((length = gzis.read(buffer)) >= 0)
                    {
                        baos.write(buffer, 0, length);
                    } // end while: reading input
                    
                    // No error? Getter new bytes.
                    bytes = baos.toByteArray();
                    
                } // end try
                catch (java.io.IOException e)
                {
                    // Just return originally-decoded bytes
                } // end catch
                finally
                {
                    try
                    {
                        baos.close();
                    }
                    catch (Exception e)
                    {
                    }
                    try
                    {
                        gzis.close();
                    }
                    catch (Exception e)
                    {
                    }
                    try
                    {
                        bais.close();
                    }
                    catch (Exception e)
                    {
                    }
                } // end finally
                
            } // end if: gzipped
        } // end if: bytes.length >= 2
        
        return bytes;
    } // end decode
    
    /**
     * Decodes four bytes from array <var>source</var> and writes the resulting
     * bytes (up to three of them) to <var>destination</var>. The source and
     * destination arrays can be manipulated anywhere along their length by
     * specifying <var>srcOffset</var> and <var>destOffset</var>. This method
     * does not check to make sure your arrays are large enough to accomodate
     * <var>srcOffset</var> + 4 for the <var>source</var> array or
     * <var>destOffset</var> + 3 for the <var>destination</var> array. This
     * method returns the actual number of bytes that were converted from the
     * Base64 encoding.
     * 
     * 
     * @param source
     *            the array to convert
     * @param srcOffset
     *            the index where conversion begins
     * @param destination
     *            the array to hold the conversion
     * @param destOffset
     *            the index where output will be put
     * @return the number of decoded bytes converted
     * @since 1.3
     */
    private static int decode4to3(byte[] source, int srcOffset,
            byte[] destination, int destOffset)
    {
        // Example: Dk==
        if (source[srcOffset + 2] == EQUALS_SIGN)
        {
            // Two ways to do the same thing. Don't know which way I like best.
            // int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6
            // )
            // | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 );
            int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18)
                    | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12);
            
            destination[destOffset] = (byte)(outBuff >>> 16);
            return 1;
        }
        
        // Example: DkL=
        else if (source[srcOffset + 3] == EQUALS_SIGN)
        {
            // Two ways to do the same thing. Don't know which way I like best.
            // int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6
            // )
            // | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
            // | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 );
            int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18)
                    | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
                    | ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6);
            
            destination[destOffset] = (byte)(outBuff >>> 16);
            destination[destOffset + 1] = (byte)(outBuff >>> 8);
            return 2;
        }
        
        // Example: DkLE
        else
        {
            try
            {
                // Two ways to do the same thing. Don't know which way I like
                // best.
                // int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 )
                // >>> 6 )
                // | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
                // | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 )
                // | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 );
                int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18)
                        | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
                        | ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6)
                        | ((DECODABET[source[srcOffset + 3]] & 0xFF));
                
                destination[destOffset] = (byte)(outBuff >> 16);
                destination[destOffset + 1] = (byte)(outBuff >> 8);
                destination[destOffset + 2] = (byte)(outBuff);
                
                return 3;
            }
            catch (Exception e)
            {
                System.out.println("" + source[srcOffset] + ": "
                        + (DECODABET[source[srcOffset]]));
                System.out.println("" + source[srcOffset + 1] + ": "
                        + (DECODABET[source[srcOffset + 1]]));
                System.out.println("" + source[srcOffset + 2] + ": "
                        + (DECODABET[source[srcOffset + 2]]));
                System.out.println("" + source[srcOffset + 3] + ": "
                        + (DECODABET[source[srcOffset + 3]]));
                return -1;
            } // e nd catch
        }
    } // end decodeToBytes
    
    /**
     * Convenience method for reading a base64-encoded file and decoding it.
     * 
     * @param filename
     *            Filename for reading encoded data
     * @return decoded byte array or null if unsuccessful
     * 
     * @since 1.0
     */
    public static byte[] decodeFromFile(String filename)
    {
        byte[] decodedData = null;
        Base64.InputStream bis = null;
        try
        {
            // Setter up some useful variables
            java.io.File file = new java.io.File(filename);
            byte[] buffer = null;
            int length = 0;
            int numBytes = 0;
            
            // Check for size of file
            if (file.length() > Integer.MAX_VALUE)
            {
                System.err
                        .println("File is too big for this convenience method ("
                                + file.length() + " bytes).");
                return null;
            } // end if: file too big for int index
            buffer = new byte[(int)file.length()];
            
            // Open a stream
            bis = new Base64.InputStream(new java.io.BufferedInputStream(
                    new java.io.FileInputStream(file)), Base64.DECODE);
            
            // Read until done
            while ((numBytes = bis.read(buffer, length, 4096)) >= 0)
                length += numBytes;
            
            // Save in a variable to return
            decodedData = new byte[length];
            System.arraycopy(buffer, 0, decodedData, 0, length);
            
        } // end try
        catch (java.io.IOException e)
        {
            System.err.println("Error decoding from file " + filename);
        } // end catch: IOException
        finally
        {
            try
            {
                bis.close();
            }
            catch (Exception e)
            {
            }
        } // end finally
        
        return decodedData;
    } // end decodeFromFile
    
    /**
     * Convenience method for decoding data to a file.
     * 
     * @param dataToDecode
     *            Base64-encoded data as a string
     * @param filename
     *            Filename for saving decoded data
     * @return <tt>true</tt> if successful, <tt>false</tt> otherwise
     * 
     * @since 1.0
     */
    public static boolean decodeToFile(String dataToDecode, String filename)
    {
        boolean success = false;
        Base64.OutputStream bos = null;
        try
        {
            bos = new Base64.OutputStream(
                    new java.io.FileOutputStream(filename), Base64.DECODE);
            bos.write(dataToDecode.getBytes(PREFERRED_ENCODING));
            success = true;
        } // end try
        catch (java.io.IOException e)
        {
            success = false;
        } // end catch: IOException
        finally
        {
            try
            {
                bos.close();
            }
            catch (Exception e)
            {
            }
        } // end finally
        
        return success;
    } // end decodeToFile
    
    /**
     * Attempts to decode Base64 data and deserialize a Java Object within.
     * Returns <tt>null</tt> if there was an error.
     * 
     * @param encodedObject
     *            The Base64 data to decode
     * @return The decoded and deserialized object
     * @since 1.5
     */
    public static Object decodeToObject(String encodedObject)
        throws Exception
    {
        // Decode and gunzip if necessary
        byte[] objBytes = decode(encodedObject);
        
        java.io.ByteArrayInputStream bais = null;
        java.io.ObjectInputStream ois = null;
        Object obj = null;
        
        try
        {
            bais = new java.io.ByteArrayInputStream(objBytes);
            ois = new java.io.ObjectInputStream(bais);
            
            obj = ois.readObject();
        } // end try
        finally
        {
            try
            {
                bais.close();
            }
            catch (Exception e)
            {
            }
            try
            {
                ois.close();
            }
            catch (Exception e)
            {
            }
        } // end finally
        
        return obj;
    } // end decodeObject
    
    /**
     * Encodes up to the first three bytes of array <var>threeBytes</var> and
     * returns a four-byte array in Base64 notation. The actual number of
     * significant bytes in your array is given by <var>numSigBytes</var>. The
     * array <var>threeBytes</var> needs only be as big as
     * <var>numSigBytes</var>. Code can reuse a byte array by passing a
     * four-byte array as <var>b4</var>.
     * 
     * @param b4
     *            A reusable byte array to reduce array instantiation
     * @param threeBytes
     *            the array to convert
     * @param numSigBytes
     *            the number of significant bytes in your array
     * @return four byte array in Base64 notation.
     * @since 1.5.1
     */
    private static byte[] encode3to4(byte[] b4, byte[] threeBytes,
            int numSigBytes)
    {
        encode3to4(threeBytes, 0, numSigBytes, b4, 0);
        return b4;
    } // end encode3to4
    
    /* ******** D E C O D I N G M E T H O D S ******** */

    /**
     * Encodes up to three bytes of the array <var>source</var> and writes the
     * resulting four Base64 bytes to <var>destination</var>. The source and
     * destination arrays can be manipulated anywhere along their length by
     * specifying <var>srcOffset</var> and <var>destOffset</var>. This method
     * does not check to make sure your arrays are large enough to accomodate
     * <var>srcOffset</var> + 3 for the <var>source</var> array or
     * <var>destOffset</var> + 4 for the <var>destination</var> array. The
     * actual number of significant bytes in your array is given by
     * <var>numSigBytes</var>.
     * 
     * @param source
     *            the array to convert
     * @param srcOffset
     *            the index where conversion begins
     * @param numSigBytes
     *            the number of significant bytes in your array
     * @param destination
     *            the array to hold the conversion
     * @param destOffset
     *            the index where output will be put
     * @return the <var>destination</var> array
     * @since 1.3
     */
    private static byte[] encode3to4(byte[] source, int srcOffset,
            int numSigBytes, byte[] destination, int destOffset)
    {
        // 1 2 3
        // 01234567890123456789012345678901 Bit position
        // --------000000001111111122222222 Array position from threeBytes
        // --------| || || || | Six bit groups to index ALPHABET
        // >>18 >>12 >> 6 >> 0 Right shift necessary
        // 0x3f 0x3f 0x3f Additional AND
        
        // Create buffer with zero-padding if there are only one or two
        // significant bytes passed in the array.
        // We have to shift left 24 in order to flush out the 1's that appear
        // when Java treats a value as negative that is cast from a byte to an
        // int.
        int inBuff = (numSigBytes > 0 ? ((source[srcOffset] << 24) >>> 8) : 0)
                | (numSigBytes > 1 ? ((source[srcOffset + 1] << 24) >>> 16) : 0)
                | (numSigBytes > 2 ? ((source[srcOffset + 2] << 24) >>> 24) : 0);
        
        switch (numSigBytes)
        {
            case 3:
                destination[destOffset] = ALPHABET[(inBuff >>> 18)];
                destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
                destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
                destination[destOffset + 3] = ALPHABET[(inBuff) & 0x3f];
                return destination;
                
            case 2:
                destination[destOffset] = ALPHABET[(inBuff >>> 18)];
                destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
                destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
                destination[destOffset + 3] = EQUALS_SIGN;
                return destination;
                
            case 1:
                destination[destOffset] = ALPHABET[(inBuff >>> 18)];
                destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
                destination[destOffset + 2] = EQUALS_SIGN;
                destination[destOffset + 3] = EQUALS_SIGN;
                return destination;
                
            default:
                return destination;
        } // end switch
    } // end encode3to4
    
    /**
     * Encodes a byte array into Base64 notation. Does not GZip-compress data.
     * 
     * @param source
     *            The data to convert
     * @since 1.4
     */
    public static String encodeBytes(byte[] source)
    {
        return encodeBytes(source, 0, source.length, NO_OPTIONS);
    } // end encodeBytes
    
    /**
     * Encodes a byte array into Base64 notation.
     * <p>
     * Valid options:
     * 
     * <pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DONT_BREAK_LINES: don't break lines at 76 characters
     *     &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
     * </pre>
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
     * <p>
     * Example:
     * <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     * 
     * 
     * @param source
     *            The data to convert
     * @param options
     *            Specified options
     * @see Base64#GZIP
     * @see Base64#DONT_BREAK_LINES
     * @since 1.0
     */
    public static String encodeBytes(byte[] source, int options)
    {
        return encodeBytes(source, 0, source.length, options);
    } // end encodeBytes
    
    /**
     * Encodes a byte array into Base64 notation. Does not GZip-compress data.
     * 
     * @param source
     *            The data to convert
     * @param off
     *            Offset in array where conversion should begin
     * @param len
     *            Length of data to convert
     * @since 1.4
     */
    public static String encodeBytes(byte[] source, int off, int len)
    {
        return encodeBytes(source, off, len, NO_OPTIONS);
    } // end encodeBytes
    
    /**
     * Encodes a byte array into Base64 notation.
     * <p>
     * Valid options:
     * 
     * <pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DONT_BREAK_LINES: don't break lines at 76 characters
     *     &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
     * </pre>
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
     * <p>
     * Example:
     * <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     * 
     * 
     * @param source
     *            The data to convert
     * @param off
     *            Offset in array where conversion should begin
     * @param len
     *            Length of data to convert
     * @param options
     *            Specified options
     * @see Base64#GZIP
     * @see Base64#DONT_BREAK_LINES
     * @since 1.0
     */
    public static String encodeBytes(byte[] source, int off, int len,
            int options)
    {
        // Isolate options
        int dontBreakLines = (options & DONT_BREAK_LINES);
        int gzip = (options & GZIP);
        
        // Compress?
        if (gzip == GZIP)
        {
            java.io.ByteArrayOutputStream baos = null;
            java.util.zip.GZIPOutputStream gzos = null;
            Base64.OutputStream b64os = null;
            
            try
            {
                // GZip -> Base64 -> ByteArray
                baos = new java.io.ByteArrayOutputStream();
                b64os = new Base64.OutputStream(baos, ENCODE | dontBreakLines);
                gzos = new java.util.zip.GZIPOutputStream(b64os);
                
                gzos.write(source, off, len);
                gzos.close();
            } // end try
            catch (java.io.IOException e)
            {
                e.printStackTrace();
                return null;
            } // end catch
            finally
            {
                try
                {
                    gzos.close();
                }
                catch (Exception e)
                {
                }
                try
                {
                    b64os.close();
                }
                catch (Exception e)
                {
                }
                try
                {
                    baos.close();
                }
                catch (Exception e)
                {
                }
            } // end finally
            
            // Return value according to relevant encoding.
            try
            {
                return new String(baos.toByteArray(), PREFERRED_ENCODING);
            } // end try
            catch (java.io.UnsupportedEncodingException uue)
            {
                return new String(baos.toByteArray());
            } // end catch
        } // end if: compress
        
        // Else, don't compress. Better not to use streams at all then.
        else
        {
            // Convert option to boolean in way that code likes it.
            boolean breakLines = dontBreakLines == 0;
            
            int len43 = len * 4 / 3;
            byte[] outBuff = new byte[(len43) // Main 4:3
                    + ((len % 3) > 0 ? 4 : 0) // Account for padding
                    + (breakLines ? (len43 / MAX_LINE_LENGTH) : 0)]; // New
                                                                     // lines
            int d = 0;
            int e = 0;
            int len2 = len - 2;
            int lineLength = 0;
            for (; d < len2; d += 3, e += 4)
            {
                encode3to4(source, d + off, 3, outBuff, e);
                
                lineLength += 4;
                if (breakLines && lineLength == MAX_LINE_LENGTH)
                {
                    outBuff[e + 4] = NEW_LINE;
                    e++;
                    lineLength = 0;
                } // end if: end of line
            } // en dfor: each piece of array
            
            if (d < len)
            {
                encode3to4(source, d + off, len - d, outBuff, e);
                e += 4;
            } // end if: some padding needed
            
            // Return value according to relevant encoding.
            try
            {
                return new String(outBuff, 0, e, PREFERRED_ENCODING);
            } // end try
            catch (java.io.UnsupportedEncodingException uue)
            {
                return new String(outBuff, 0, e);
            } // end catch
            
        } // end else: don't compress
        
    } // end encodeBytes
    
    /**
     * Convenience method for reading a binary file and base64-encoding it.
     * 
     * @param filename
     *            Filename for reading binary data
     * @return base64-encoded string or null if unsuccessful
     * 
     * @since 1.0
     */
    public static String encodeFromFile(String filename)
    {
        String encodedData = null;
        Base64.InputStream bis = null;
        try
        {
            // Setter up some useful variables
            java.io.File file = new java.io.File(filename);
            byte[] buffer = new byte[(int)(file.length() * 1.4)];
            int length = 0;
            int numBytes = 0;
            
            // Open a stream
            bis = new Base64.InputStream(new java.io.BufferedInputStream(
                    new java.io.FileInputStream(file)), Base64.ENCODE);
            
            // Read until done
            while ((numBytes = bis.read(buffer, length, 4096)) >= 0)
                length += numBytes;
            
            // Save in a variable to return
            encodedData = new String(buffer, 0, length,
                    Base64.PREFERRED_ENCODING);
            
        } // end try
        catch (java.io.IOException e)
        {
            System.err.println("Error encoding from file " + filename);
        } // end catch: IOException
        finally
        {
            try
            {
                bis.close();
            }
            catch (Exception e)
            {
            }
        } // end finally
        
        return encodedData;
    } // end encodeFromFile
    
    /**
     * Serializes an object and returns the Base64-encoded version of that
     * serialized object. If the object cannot be serialized or there is another
     * error, the method will return <tt>null</tt>. The object is not
     * GZip-compressed before being encoded.
     * 
     * @param serializableObject
     *            The object to encode
     * @return The Base64-encoded object
     * @since 1.4
     */
    public static String encodeObject(java.io.Serializable serializableObject)
    {
        return encodeObject(serializableObject, NO_OPTIONS);
    } // end encodeObject
    
    /**
     * Serializes an object and returns the Base64-encoded version of that
     * serialized object. If the object cannot be serialized or there is another
     * error, the method will return <tt>null</tt>.
     * <p>
     * Valid options:
     * 
     * <pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DONT_BREAK_LINES: don't break lines at 76 characters
     *     &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
     * </pre>
     * <p>
     * Example: <code>encodeObject( myObj, Base64.GZIP )</code> or
     * <p>
     * Example:
     * <code>encodeObject( myObj, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     * 
     * @param serializableObject
     *            The object to encode
     * @param options
     *            Specified options
     * @return The Base64-encoded object
     * @see Base64#GZIP
     * @see Base64#DONT_BREAK_LINES
     * @since 1.0
     */
    public static String encodeObject(java.io.Serializable serializableObject,
            int options)
    {
        // Streams
        java.io.ByteArrayOutputStream baos = null;
        java.io.OutputStream b64os = null;
        java.io.ObjectOutputStream oos = null;
        java.util.zip.GZIPOutputStream gzos = null;
        
        // Isolate options
        int gzip = (options & GZIP);
        int dontBreakLines = (options & DONT_BREAK_LINES);
        
        try
        {
            // ObjectOutputStream -> (GZIP) -> Base64 -> ByteArrayOutputStream
            baos = new java.io.ByteArrayOutputStream();
            b64os = new Base64.OutputStream(baos, ENCODE | dontBreakLines);
            
            // GZip?
            if (gzip == GZIP)
            {
                gzos = new java.util.zip.GZIPOutputStream(b64os);
                oos = new java.io.ObjectOutputStream(gzos);
            } // end if: gzip
            else
                oos = new java.io.ObjectOutputStream(b64os);
            
            oos.writeObject(serializableObject);
        } // end try
        catch (java.io.IOException e)
        {
            e.printStackTrace();
            return null;
        } // end catch
        finally
        {
            try
            {
                oos.close();
            }
            catch (Exception e)
            {
            }
            try
            {
                gzos.close();
            }
            catch (Exception e)
            {
            }
            try
            {
                b64os.close();
            }
            catch (Exception e)
            {
            }
            try
            {
                baos.close();
            }
            catch (Exception e)
            {
            }
        } // end finally
        
        // Return value according to relevant encoding.
        try
        {
            return new String(baos.toByteArray(), PREFERRED_ENCODING);
        } // end try
        catch (java.io.UnsupportedEncodingException uue)
        {
            return new String(baos.toByteArray());
        } // end catch
        
    } // end encode
    
    /* ******** I N N E R C L A S S I N P U T S T R E A M ******** */

    /**
     * Convenience method for encoding data to a file.
     * 
     * @param dataToEncode
     *            byte array of data to encode in base64 form
     * @param filename
     *            Filename for saving encoded data
     * @return <tt>true</tt> if successful, <tt>false</tt> otherwise
     * 
     * @since 1.0
     */
    public static boolean encodeToFile(byte[] dataToEncode, String filename)
    {
        boolean success = false;
        Base64.OutputStream bos = null;
        try
        {
            bos = new Base64.OutputStream(
                    new java.io.FileOutputStream(filename), Base64.ENCODE);
            bos.write(dataToEncode);
            success = true;
        } // end try
        catch (java.io.IOException e)
        {
            
            success = false;
        } // end catch: IOException
        finally
        {
            try
            {
                bos.close();
            }
            catch (Exception e)
            {
            }
        } // end finally
        
        return success;
    } // end encodeToFile
    
    /* ******** I N N E R C L A S S O U T P U T S T R E A M ******** */

    /** Defeats instantiation. */
    private Base64()
    {
    }
    
} // end class Base64
